Replace Injection Pump and ....

[David_Jennings]

Hello diesel page, it has been a while. I have had 17 years of relatively trouble-free ownership with my 1999 K2500 6.5. I installed a remote PMD cooler, and other than the darn wheel bearings, she has been a great truck. I bought the truck in the first place because of this website: it cleared away all the myth and fear about owning one of these trucks, and allowed me to get a fantastic price from someone who was overwhelmed by all the horrible things people say about them. Thank you again for that.

I have thoroughly enjoyed Big Red, and was just about to list her on Craigslist when a storm dropped a Madrona branch on her hood. At 18 years of age, Red was no longer pretty, but the branch pushed her appearance into the work-truck category. Still, I was fortunate to have insurance coverage, so I kept the claim money and decided to drop the price to reflect the relatively small (but expensive) dent on the hood.

Two weeks later, on the way to work, she died suddenly. No stuttering, no balking, just dead, dead, dead. The same thing happened 4 months earlier when my son was driving her, but he manages to break everything he drives, so I thought little of it. Of course it had to be the PMD. It is always the PMD. I replaced the PMD 9 months earlier, but it nonetheless still had to be the PMD. I had it towed to a local mechanic I like and trust who has training on GM diesels. (He sold me the last PMD, and it was still under warranty.) Anyway, my mechanic informed me, after testing, that he is 100% certain that the injection pump is bad. Period. The price for replacement, of course, is exactly what the insurance company paid me for the damage to the hood. I had her towed to my home so I could fully explore the problem.

Of course I intend to replace the PMD myself and to check for fuel and do all the diagnostics recommended before I actually replace the pump, but the mechanic says he did all those things. Assuming I have to replace the pump, which I intend to do myself, I would greatly appreciate a couple pieces of advice from other 6.5 owners.

1. Are there any good step-by-step guides for replacing the injection pump?
2. If I really have to go through with this, what else should I replace while I am in there? The truck has about 105K miles. Injectors are original, but glow plugs have been replaced. I was planning on selling her, but I’m not going to scrimp on parts at the expense of the next owner.
3. Does anyone think it is possible that the impact from the 200 pound branch could have caused this? Seems impossible, but the dent is precisely on top of the pump valley.

Thank you in advance for your thoughts.

David Reese Jennings on Vashon

[rustyk]

Before you tear down, check the lift pump - both the pump and the oil pressure sender that supplies power. It rare for an IP to quit suddenly.

[a5150nut]

Did your dent go deep enough to reach the shut off solenoid or the wire going to it?

[JohnC]

It rare for an IP to quit suddenly.

Especially without codes. A mechanical failure wouldn't have happened twice, so it must be electrical or external to the pump.

[ronale]

Check extension cable to pmd. Try to connect pmd to original plug close to ip.
Lots of junk extensions cables.

[David_Jennings]

Thanks. I will first try a replacement cable and then focus on the oil pressure sending unit. The lift pump should be a simple test too. I will also read up on how to test the fuel cutoff solenoid.

I always thought I'd get some warning with a faulty pump. This time it just shut down while driving 35 mph. No stuttering, no threadiness; just dead.

[JohnC]

I always thought I'd get some warning with a faulty pump. This time it just shut down while driving 35 mph. No stuttering, no threadiness; just dead.

The PMD also reports Fuel solenoid closure time to the PCM. If it gets an error or nothing it figures it cannot control the fuel solenoid so the engine is in danger of running away. It (the PCM) immediately drops the fuel shutoff solenoid and the engine stalls even if there were no obvious symptoms.

[David_Jennings]

Thanks to everyone who replied. I think Ronale nailed it. I bought a new PMD extension cable and a new oil pressure sending unit. I replaced the cable first ($10.00), and once I had it out I found the nibbling in the picture below. It's obviously time to hang socks filled with mothballs in the engine bay again. Anyway, it started up immediately and runs fine. I may be too optimistic, but Big Red seems to be fixed. The Diesel Page does it again, big-time--I may have eluded a very expensive repair. I couldn't be happier.